Currently, standardization of a 4G wireless communication system is ongoing in 3GPP (Third Generation Partnership Project). Using a technique such as relay, carrier aggregation, or the like according to 4G, it is possible to realize an increase in maximum communication speed or improvement in quality at a cell edge. Also, examination is being carried out on improvement in coverage by introducing a base station, such as an HeNodeB (Home eNodeB), a femto-cell base station, a small base station for cellular phones), an RHH (Remote Radio Head), or the like, other than an eNodeB (macro-cell base station).
In such a wireless communication system, UE (User Equipment: user terminal) synchronizes frames with a base station based on a synchronization signal transmitted from the base station, and then synchronizes an oscillator in the UE with an oscillator of the base station with high accuracy. Each piece of UE performs time adjustment in accordance with the distance between the base station and the piece of UE, which is referred to as Timing Advance, so that wireless signals transmitted from a plurality of user terminals can be received by the base station at the same time. Specifically, Timing Advance is performed during a random access procedure in which a user terminal transmits a preamble for a random access window. From a relationship between a time when the preamble arrives at the base station and the random access window, it is possible to acquire a Timing Advance value. Such random access is disclosed in Patent Literature 1, Patent Literature 2, and the like.
Meanwhile, MTC (Machine Type Communications) has also been under discussion in 3GPP. In general, MTC has the same meaning as M2M (Machine to Machine), and denotes communication that is not directly used by humans between a machine and another machine. This MTC is mainly performed between a server and an MTC terminal that is not directly used by humans.
For example, in a medical MTC application, an MTC terminal may collect electrocardiogram information on a human and transmit the electrocardiogram information to a server using an uplink when a trigger condition is satisfied. Also in another MTC application, a vending machine may be caused to function as an MTC terminal, and a server may be caused to report sales of the vending machine under management at predetermined periods (for example, 30 days).